What does the y-int of a velocity-time graph represent?

[PhysicsJunkie]

Homework Statement

I collected data from a cart accelerating down an inclined track and made a velocity-time graph from the position-time graph.
What does the y-int of my v-t graph represent?

2. The attempt at a solution

I know that it represents the initial velocity of the motion. But what exatly does this initial velocity represent?

 

[Delphi51]

What more can be said about initial velocity?
This is the speed at the time you called zero.

 

[Dopefish1337]

Did you start your timing immediately after releasing the cart from rest?